封闭型内陆湖泊夏季氮素赋存特征——以达里诺尔湖为例

氮素是影响湖泊初级生产力的主要因素之一。近年来,受气候干旱及上游用水量增加等因素的影响,大多数封闭性内陆湖都面临着湖面萎缩、湖水因营养盐浓度增加而逐渐恶化的问题。本文以内蒙古高原境内封闭型内陆湖泊——达里诺尔湖为例,于2017年夏季采集湖水、间隙水、沉积物、入湖河流等样品。对湖泊氮素赋存特征、迁移趋势做出分析,并且对入湖河流携带的氮素对湖泊水质的影响展开讨论。结果表明:氨氮(NH_4~+-N)是上覆水中占比例最高的形态氮。总氮(TN)、硝酸盐氮(NO_3~--N)、亚硝酸盐氮(NO_2~--N)含量随水深从浅到深基本保持不变。只有B6、E2、E5样点的NH_4~+-N在水深1.5 m向下处含量有所波动。表层沉积物TN均值2 809.97 mg·kg~(-1),可交换态氮占TN含量6.74%;河水中占比例最高的形态氮是NO_3~--N,四条入湖河流中,TN、NH_4~+-N含量最高的是沙里河,NO_3~--N含量最高的是亮子河;每年由入湖河流携带入湖的TN量为120 t。总体来看,达里诺尔湖氮素赋存特征为:NH_4~+-N是上覆水的主导形态氮,TN及各形态氮含量在不同深度水层掺混均匀,无明显的分层现象。沉积物TN含量较高且氮素迁移能力较强。TN、NO_3~--N、NO_2~--N表现为由沉积物到上覆水的释放状态,而NH_4~+-N则以上覆水到沉积物的吸附状态为主。河流的输入对湖水TN含量有稀释作用,但会增加湖水NO_3~--N的负荷。     

14条环太湖河流水质与茭草、水花生氮磷含量

选取环太湖14条主要河流为研究对象,分析河流水质和水生植物优势种(水花生和茭草)中氮磷含量,探讨两者的相关性。结果表明:自实施综合整治以来,环太湖河流水质有所好转,氮污染是目前环太湖河流的主要污染特征,有效削减其入河量是太湖入湖河流治理的重要任务;水花生总氮(TN)和总磷(TP)累积能力均强于茭草,水花生叶(茎)中TN、TP含量分别是33.88～55.70g·kg-(122.10～29.96g·kg-1)、4.44～8.96g·kg-(13.43～8.02g·kg-1);茭草叶(茎)中TN、TP含量分别是12.30～21.41g·kg-(121.75～31.22g·kg-1)、2.06～6.58g·kg-(12.60～7.81g·kg-1)。水花生和茭草叶茎中TN含量与水体中TN浓度均无显著相关性,但两种植物叶茎中TP含量与水体中TP浓度呈显著正相关,即在一定浓度范围内,水体中P浓度越高,水花生和茭草体内P的累积量越大。     

Development of fish-based assessment method for the ecological status of rivers in the Baltic region

Abstract  A fish-based assessment method for determining the ecological status of rivers in the southern part of the Baltic region was developed, classifying fish assemblages of near natural sites, and testing the response of a wide range of fish metrics to human pressure. However, the potential for developing a statistically robust method was limited because of insufficient data and the impact of fishery exploitation. A combination of expert judgement, historical data and spatially based methods were needed to establish reference conditions and classification criteria for fish metrics. The final list of metrics (6–9 metrics per six different river types) comprises five ecological guilds (feeding, overall tolerance, habitat, migration and spawning strategy) and three sentinel (dominant) species ( Salmo trutta L., Cottus gobio L. and Alburnoides bipunctatus [Bloch]). The method tends to underscore the ecological status of specific river types because the selected metrics probably do not account for all possible variability in fish community response to degradation, as some community-specific characteristics were poorly or not represented. Exploitation pressure might have considerable effects on functionality of fish metrics. Results suggest that the method needs modification to account for these limitations.     

Inter-calibration of three electric fishing techniques to estimate 0+ juvenile fish densities on sandy river beaches

Abstract  The efficiencies of three different techniques for 0+ fish point abundance sampling by electric fishing were tested on a sandy beach of the Morava River, Czech Republic. During direct electric fishing (DE), the operator immerses an anode fastened on an extension pole. During thrown anode electric fishing (TE), the anode is thrown at a distance from the bank. During remote electric fishing (RE), a pre-positioned anode is activated after allowing sufficient time for fish to recolonise the area. The DE technique was found to disturb fish and that fish tend to escape, thereby reducing its efficiency (30% of efficiency of RE). There was no significant difference in relative abundance estimates or size structure of assemblages between DE and RE, but TE seemed to be a species selective technique on sandy river beaches, significantly overestimating relative abundance of bleak. Of the three techniques tested, RE was the most efficient and if time required for deployment could be reduced, it would be also the most suitable for monitoring 0+ fish assemblages on sandy river beaches.     

补水对采金废弃矿区恢复效益的影响

以阿勒泰两河源自然保护区采金废弃矿区为研究对象,从地形、水、土和生物多方面开展矿山生态恢复试验,分析了推平、覆土、撒羊粪、水分补给、补植、撒种、羊群驻扎和漫溢措施对矿区植被的影响,结合每种措施的成本,选出恢复成效好、成本低的措施。结果显示,1)对废弃矿区进行人工灌溉后,物种数增加了21.7倍,土石比增加了4.5倍;2)滴灌、漫灌和喷灌3种措施中,漫灌措施下成效最好,对土壤的恢复中:覆土后,漫灌下的土石比分别较滴灌与喷灌高38.0%和33.1%;撒羊粪后,分别高出21.7%和11.4%;撒种后,分别高8.9%和8.5%;补植种黑加仑(Ribes nigrum)后,分别高24.2%和2.9%;3)不同灌溉方式下成本高低为滴灌喷灌漫灌,其中漫灌受地理位置限制,而喷灌则适用性广泛。阿勒泰矿山恢复中,可注重矿区的自然恢复并辅以漫灌和人工覆土等措施。本研究为其废弃矿区修复提供了一定的理论依据。     

基于河流分段与分季节的涑水河水环境容量计算及模型预测

【目的】建立适合于干旱和半干旱地区季节性河流的水环境容量计算模式及预测模型。【方法】以山西省涑水河为例,基于河流分段(上游(横水铁路桥断面以上)、中游(吕庄水库断面至横水铁路桥断面)、下游(吕庄水库断面以下))和分季节(丰水期、平水期、枯水期)的原则,在传统水环境容量计算模型的基础上,利用涑水河流域现有的水文资料、环境资料及生态、经济等资料,探索影响干旱和半干旱地区河流生态环境容量的主要因素,构建涑水河水环境容量计算模式与自适应调整粒子群-RBF神经网络预测模型,并用涑水河流域监测数据、历史资料进行验证。【结果】水体原污染物质量浓度、当前水环境的质量标准、河流距离、河流流量、排放污水量和排放时间是影响干旱和半干旱地区河流生态环境容量的主要因素。在丰水期、平水期、枯水期涑水河3个断面之间水环境容量计算值与预测值均非常接近,计算值相对误差为0.12%~1.47%,预测值相对误差为0.09%~2.02%,可见计算方法和预测方法的精度均较高。【结论】涑水河水环境容量预测值可用于指导涑水河水资源优化配置和水环境污染控制,对推动干旱和半干旱地区流域的可持续发展具有积极意义。     

南汀河流域土壤侵蚀的时空分异

[目的]分析南汀河流域坡面土壤侵蚀的时空分异特征,为流域水土保持和边疆生态环境建设提供科学参考。[方法]基于通用土壤流失方程(USLE),运用RS和GIS技术计算南汀河流域1990,2000及2010年3个时段的土壤侵蚀模数。[结果]3个时段内研究区侵蚀模数呈现先升后降的趋势,年均侵蚀模数从24.75t/(hm2·a)升到30.05t/(hm2·a),然后降为25.87t/(hm2·a)。3个时段内,流域内强烈侵蚀及其以上的侵蚀面积仅占总侵蚀面积的19.94%,但对流域总侵蚀量的贡献高达73.56%。1990—2000年,强烈及强烈以下侵蚀面积减少了1 059.85km2,强烈侵蚀以上的侵蚀面积则增加了112.29km2;2000—2010年,微度侵蚀面积有小幅增加,其余侵蚀等级的侵蚀面积都有所下降。当坡度小于20°时,侵蚀模数随着坡度的增加而增加,坡度超过20°后,侵蚀模数有降低的趋势;从海拔上看,高侵蚀模数区域主要位于海拔500~2 000m范围。[结论]流域内的土壤侵蚀治理已初见成效,但在局部地区,土壤侵蚀仍有加剧现象。     

湖南四水流域洪涝灾害特性与减灾战略

湖南湘资沅澧四水均属山区暴雨型河流 ,汛期洪涝灾害频发。通过对四水流域近数 10 a洪涝灾害资料分析表明 :洪涝灾害发生频率高 ,且具有多发性、共生性与地域差异性的整体特征。在时间分布上呈现明显的季节性、连年性和循环周期性 ;在空间分布上 ,中上游山丘区山洪灾害频发 ,中下游河谷平原洪涝灾害交织 ,下游尾闾洪溃涝渍灾害并发。随着时间的演进 ,洪涝灾损和发生频率均呈明显的增大趋势 ,据此提出了减灾战略以减轻洪涝灾害损失。     

Sediment Dynamics and Pollutant Mobility in Rivers (SEDYMO): Assessing Catchment-Wide Emission-Immission Relationships from Sediment Studies. BMBF Coordinated Research Project SEDYMO (2002–2006)

-  DOI: http://dx.doi.org/10.1065/jss2005.11.002 Background and Scope. Apart from their function as indicator or memory for local pollutant inputs, sediments, and especially sediment cores, can be used as a tool for assessing emissionimmission relationships of contaminants on a river-basin scale. Methods. In the framework of the SEDYMO program, source effects, i.e. intensity of sediment erosion under different shear stress, were investigated using a combination of core profile or sampling box studies in laboratory flumes and a mobile in-situ testing device for sediment stability. Results. Calculations of immission risks on downstream areas, e.g., from a three-step approach (substances of concern, areas of concern, areas of risk; Heise et al. 2004), may be directly confirmed from sediment core data, specifically from flood layers, at the target site.     

Proliferative kidney disease in Switzerland: current state of knowledge

This study presents an overview of the distribution of proliferative kidney disease (PKD) in wild and farmed fish in Switzerland based on two sources: (1) the results of routine diagnostic work at the National Fish Disease Laboratory, and (2) the results of a country‐wide survey for PKD. The first case of PKD in Switzerland was diagnosed in 1979 and since 1981, a few cases have been found every year. Affected species were rainbow trout, brown trout and grayling from rivers and fish farms. Most of the diseased fish were found in the lower altitude regions of the country (Swiss midlands). A seasonal distribution of the cases was evident: PKD‐positive fish occurred only from June to November withprominent peaks in August and September. Among infected fish all length classes were present, but the highest numbers of affected fish were found in the length classes <10 cm and 16–20 cm. The evaluation of the samples from a survey of the occurrence of PKD in 2000/2001 revealed a much broader geographical distribution of the infection than expected from routine diagnostic observations. Fish from 56 of 139 rivers analysed by histological examination were positive for parasites. Fish from 131 of these sites were examined macroscopically. Of these, trout from 45 sites showed gross alterations indicative for PKD. Most of the positive fish were found in the Swiss midlands north of the Alps. Fish from six of 65 fish farms investigated were found to be PKD‐positive by histopathological analysis, and in four of these cases fish could be identified as infected on the basis of gross examination.